The present invention is related to an ink jet recording apparatus operated in such a manner that a moving position of a capping device is changed during both flushing operation and capping operation in accordance with an adjusting amount of a platen gap by a platen gap adjuster, and is also related to a moving position control method of the capping device, and is further related to a flushing control method used in an ink jet recording apparatus operated in such a manner that a flushing operation mode is changed in accordance with an adjusting amount of a platen gap.
For instance, an ink jet recording apparatus of a serial printing system is equipped with an ink jet recording head, and a paper feeding means. While the ink jet recording head is mounted on a carriage, this ink jet recording head is transported along a main scanning direction. The paper feeding means feeds recording paper sheets along a sub-scanning direction located perpendicular to the above-described main scanning direction. Since ink droplets are jetted from the recording head in accordance with print data, a printing operation is carried out with respect to the recording paper sheets.
The above-described ink jet recording head owns the below-mentioned problem in connection with such a printing operation that ink which is pressured in a pressure producing chamber is jetted as ink droplets from nozzle openings onto recording paper sheets. That is to say, the ink viscosity is increased due to evaporation of ink solvent from the nozzle openings, the ink is caked, and dust is attached to the nozzle openings, so that the normal jetting operation of the ink droplets from the nozzle openings is disturbed, resulting in an occurrence of a printing failure.
To avoid this problem, this sort of ink jet recording apparatus are equipped with capping device capable of capping, or sealing nozzle forming surfaces of recording heads while printing operations thereof are set under rest conditions. This capping device may have not only a function of a lid, but also a jetting function recovering means of ink droplets. This lid function is capable of preventing ink of the nozzle openings in the recording head from being dried. The ink droplets jetting function recovering means is capable of solving clogging of the nozzle openings in the case that the ink clogs the nozzle openings in such a manner that the nozzle forming surfaces are capped, and negative pressure is applied from a suction pump so as to suck/eject the ink from the clogging nozzle openings. As a result, clogging problems of the nozzle opening can be solved.
A process operation for forcibly sucking/ejecting ink in order to solve clogging of a recording head is generally referred to as a cleaning operation. This cleaning operation is carried out in the case that a printing operation is restarted after a long rest condition of a recording apparatus, and/or in the case that a user recognizes a printing failure and thus manipulates, for example, a cleaning switch. Then, as previously explained, after the negative pressure is applied by operating the suction pump and the ink is sucked/ejected from the recording head into the capping device, the nozzle forming surfaces are wiped by way of a wiping means which is formed by using, for instance, a rubber material and the like.
On the other hand, the above-described capping device is also equipped with a recovery means of such an ink droplet jetting function, which is provided independent from the above-explained cleaning operation. This ink droplet jetting function may flush ink droplets by applying such a drive signal to the recording head irrespective of printing operation. This recovery means is called as a flushing operation, this flushing operation is carried out every time a constant time period has elapsed in order to achieve an object capable of avoiding such a problem that clogging can be prevented, while this clogging effect occurs due to an increase in viscosity of ink located in nozzle openings from which a few amount of ink droplets is jetted while printing operation is carried out.
On the other hand, most of this sorts of recording apparatus are constructed in such a manner that the ink droplets jetted by the above-explained flushing operation are received by the above-described capping device. In this case, the following problem will occur when an interval between the nozzle forming surface of the recording head and the capping device is extremely narrow. That is, ink droplets jetted from the nozzle openings are rebounded within the capping device, and a portion of these rebounded ink droplets is again flied to the nozzle openings. As a result, meniscus of ink formed in a nozzle opening is destroyed, and thus, the normal jetting effect of the ink droplets from this nozzle opening is disturbed, so that such a printing failure called as xe2x80x9cdot skippingxe2x80x9d may occur.
Also, in such a case that an interval between the nozzle forming surface of the recording head and the capping device is wide, an occurrence of ink mist may be induced. In this ink mist, ink droplets jetted from the recording head receive air resistance and the like, so that these ink droplets are further distributed in the form of very small ink droplets, and these very small ink droplets are changed under mist state. When such ink mist is produced, various damages are given to the above sort of recording apparatus. That is, while the ink mist may float within the recording apparatus, this floating ink mist not only contaminates recording paper sheets, but also are attached to the respective drive mechanisms and printed circuit boards employed in the recording apparatus and thereafter are caked thereon. As a consequence, when the flushing operation is carried out, the above-described interval between the nozzle forming surface and the capping device should be properly controlled.
On the other hand, in this sort of recording apparatus, a platen gap adjuster is provided. This platen gap adjuster is capable of adjusting a platen gap between the recording head and the platen in correspondence with a thickness of a recording paper sheet. Then, the platen gap adjusters are generally constructed as follows. That is, when the platen gap adjuster is manipulated, the position of the recording head may be changed with respect to the platen which is arranged on a fixed position. As a result, in the case that the platen gap is adjusted, the above-described distance between the nozzle forming surface and the capping device is changed.
More specifically, nowadays, since various printing needs are made, considerably thick paper sheets are required to be used as printing paper sheets. In accordance with such a requirement, the gap adjustable range by the above-explained platen gap adjuster should be necessarily and considerably increased, as compared with the gap adjustable range of the prior art. As a consequence, the move amount of the recording head with respect to the platen is accordingly increased by manipulating the platen gap adjuster. Since such a move amount is increased, the increased move amount extremely exceeds the proper interval range between the nozzle forming surface of the recording head and the capping device, which may induce the above-described printing failure such as dot skipping, or may induce the mechanical trouble and the electrical trouble, which are caused by the occurrence of the above-described ink mist.
Also, as described above, since the platen gap is changed, the positional relationship between the nozzle forming surface of the recording head and the capping device for capping the nozzle forming surface, so that abutting pressure of the capping device with respect to the nozzle forming surface is changed. As a consequence, for instance, in such a case that the abutting pressure of the capping device with respect to the nozzle forming surface is brought into overpressure condition, another problem occurs. That is, the capping member which abuts on the nozzle forming surface is deformed. Then, in the case that the platen gap is again adjusted, and thus, the abutting pressure of the capping device with respect to the nozzle forming surface is lowered, a further problem will occur. That is, the above-explained deformation of the capping member may cause such a condition that appropriate capping (sealing) conditions cannot be established.
A recording apparatus, according to a first aspect of the present invention, has been made to solve the above-described problems. A first object of the present invention is therefore to provide an ink jet recording apparatus, and a moving position control method of a capping device employed in this ink jet recording apparatus, while such an ink jet recording apparatus is capable of adjusting positions of the capping device at both a flushing position and a capping position in correspondence with a change in platen gaps, so that both a proper flushing operation and proper capping pressure can be obtained.
Also, a recording apparatus, according to a second aspect of the present invention, has also been made to solve the above-described problems. A second object of the present invention is therefore to provide an ink jet recording apparatus, and a flushing control method for this ink jet recording apparatus, while this ink jet recording apparatus is capable of lowering an occurrence of printing failure such as the above-described dot skipping, or lowering occurrence degrees of mechanical troubles and electrical troubles caused by ink mist.
To achieve the above-described first object, the ink jet recording apparatus, according to the first aspect of the present invention, is featured by such an ink jet recording apparatus comprising: an ink jet recording head mounted on a carriage for jetting ink droplets in accordance with print data; and a capping device for capping a nozzle forming surface of the recording head; wherein when the carriage is moved to a mount portion where the capping device is mounted, the capping device is moved toward the nozzle forming surface of the recording head by receiving a driving force which moves the carriage, so that the capping device caps the nozzle forming surface; and a stopping position of the carriage in the mount portion of the capping device is adjusted based on adjustment information of a platen gap adjuster.
In this case, the capping device preferably includes a slider which is moved toward the recording head by receiving at least the driving force which moves the carriage, and a cap member mounted on the slider for capping the nozzle forming surface of the recording head, wherein when the carriage is moved, the driving force which moves the carriage is transmitted from a side of the carriage to a side of the slider through a driving force transmitting device which abuts against the slider.
Also, the slider is constructed in such a manner that the slider is moved toward the recording head being attached to a link arm rotatably mounted on a frame by receiving the driving force of the carriage through the driving force transmitting device; and a guide projection formed on the slider is slid along a guide groove formed in the frame in an inclined manner, whereby the slider is moved toward the recording head.
In this case, preferably, the ink jet recording apparatus comprises further a regulating device for retaining the guide projection formed on the slider at a predetermined position in the guide groove based on the adjustment information of the platen gap adjuster. Then, the ink jet recording apparatus is constituted in such a manner that a flushing position where the capping device is located opposite to the nozzle forming surface of the recording head with a predetermined interval and a capping position where a nozzle forming surface of the recording head is capped by the capping device, are set based on adjustment information of the platen gap adjuster.
Then, in a preferable embodiment, in the case that the adjustment information of the platen gap adjuster indicates that a platen gap is small, the guide projection formed on the slider is regulated to be retained at a lower position within the guide groove formed in the frame under inclined condition at each of the flushing position and the capping position, as compared with such a case that the adjustment information of the platen gap adjuster indicates that a platen gap is large.
Also, the ink jet recording apparatus may be arranged in such a manner that the regulating operation for retaining the guide projection at a predetermined position in the guide groove is performed by stopping a drive operation of a carriage motor for moving the carriage in the reciprocation motion.
Then, a spring member is interposed between the slider and the cap member; and the cap member abuts against the nozzle forming surface of the recording head by receiving urging force exerted by the spring member under such a condition that the nozzle forming surface of the recording head is capped by the capping device, the ink jet recording apparatus is arranged in such a manner that the regulating operation for retaining the guide projection at a predetermined position in the guide groove is performed by stopping a drive operation of a carriage motor for moving the carriage in the reciprocation motion
On the other hand, a moving position control method of a capping device, according to another aspect of the present invention, is featured by that in a moving position control method of a capping device employed in an ink jet recording apparatus comprising: an ink jet recording head mounted on a carriage transported in a reciprocation motion, for jetting ink droplets in accordance with print data; and capping device capable of capping a nozzle forming surface of the recording head; in which when the carriage is moved to a mount portion of the capping device, the capping device is moved toward the nozzle forming surface of the recording head by receiving driving force of the carriage,
the moving position control method sequentially executes: a flushing requirement judging step for judging as to whether or not the flushing operation is required; a platen gap adjustment information acquiring step for acquiring adjustment information of a platen gap adjuster in such a case that the flushing requirement judging step judges that the flushing operation is required; an interval adjusting step for controlling the moving position of the carriage to a mount portion of the capping device based upon the platen gap adjustment information acquired at the platen gap adjustment information acquiring step so as to adjust an interval between the nozzle forming surface of the recording head and the capping device at a flushing position; and a flushing step for flushing ink droplets from the recording head into the capping device, while maintaining the interval adjusted by the interval adjusting step.
In this case, the moving position control method is advanced to the flushing requirement judging step is carried out based upon a time counting operation of a flushing timer which is managed while print operation of the recording apparatus is carried out.
Moreover, a moving position control method of a capping device, according to another preferred embodiment of the present invention, is featured by that in a moving position control method of a capping device employed in an ink jet recording apparatus comprising: an ink jet recording head mounted on a carriage transported in a reciprocation motion, for jetting ink droplets in accordance with print data; and capping device capable of capping a nozzle forming surface of the recording head; in which when the carriage is moved to a mount portion of the capping device, the capping device is moved toward the nozzle forming surface of the recording head by receiving driving force of the carriage,
the moving position control method sequentially executes: a capping requirement judging step for judging as to whether or not the ink jet recording head is required to be advanced to a capping condition; a platen gap adjustment information acquiring step for acquiring adjustment information of a platen gap adjuster in such a case that the capping requirement judging step judges that the capping operation is required; and a carriage move control step for controlling the moving position of the carriage to a mount portion of the capping device based upon the platen gap adjustment information acquired in the platen gap adjustment information acquiring step.
In accordance with the recording apparatus of the first embodiment of the present invention with employment of the above-described moving position control method of the capping device, while the gap adjustment information acquired from the platen gap adjuster is utilized, the drive control of the carriage motor is carried out, and this carriage motor drives the carriage in the reciprocation motion based upon this gap adjustment information. On the other hand, the capping device is provided with the slider which is moved toward the nozzle forming surface of the recording head by receiving the driving force of the carriage. Since the cap member capable of capping the nozzle forming surface is arranged on this slider, the positional relationship between the nozzle forming surface of the recording head and the capping device can be controlled in response to the stopping position of the carriage under drive control by the carriage motor.
As a consequence, in the case that the capping device is located at the flushing position opposite to the capping device by maintaining a predetermined interval between the capping device and the nozzle forming surface of the recording head, the interval between both these members can be controlled under proper condition based upon the gap adjustment information. As a result, as previously explained, it is possible to solve such a problem that since the interval between both the members is brought into improper condition, the print failure occurs and the ink mist occurs.
Also, even in such a case that the control operation is advanced to the capping condition under which the nozzle forming surface of the recording head is capped by the capping device, the stopping position of the carriage is adjusted based upon the above-described cap adjustment information. As a result, the position of the cap member arranged on the slider can be adjusted. Therefore, the abutting pressure of the capping device capable of capping the nozzle forming surface can be controlled to the proper pressure condition.
Also, an ink jet recording apparatus according to a second embodiment of the present invention, which is accomplished so as to achieve the above-described second object, is featured by such an ink jet recording apparatus comprising: an ink jet recording head mounted on a carriage transported in a reciprocation motion, for jetting ink droplets in accordance with print data; and flushing control unit for moving the recording head to a flushing area and for applying a drive signal irrespective of a printing operation to the recording head so as to flush ink droplets into the flushing area; wherein: while a flushing operation is carried out in the flushing area, the flushing control unit adjusts an ink jetting amount of one dot during the flushing operation based upon adjustment information of a platen gap adjuster.
In this case, preferably, in the case that the adjustment information of the platen gap adjuster indicates that a platen gap is large, the flushing control unit increases the ink amount of one dot, which is jetted while the flushing operation is carried out, as compared with that of such a case that the adjustment information of the platen gap adjuster indicates that the platen gap is small.
Furthermore, preferably, in the case that the adjustment information of the platen gap adjuster indicates that a platen gap is large, the flushing control unit decreases a total number of ink droplets which are jetted from the recording head while a single flushing step is carried out, as compared with that of such a case that the adjustment information of the platen gap adjuster indicates that the platen gap is small.
Then, in the preferable embodiment, the ink droplets jetted from the recording head by executing the flushing operation are received by capping a nozzle forming surface of the recording head.
On the other hand, a flushing control method, according to a further aspect of the present invention, is featured by that in a flushing control method executed in an ink jet recording apparatus comprising: an ink jet recording head mounted on a carriage transported in a reciprocation motion, for jetting ink droplets in accordance with print data; and flushing control unit for moving the recording head to a flushing area and for applying a drive signal irrespective of a printing operation to the recording head so as to flush ink droplets into the flushing area;
the flushing control method sequentially executes: a flushing requirement judging step for judging as to whether or not the flushing operation is required; an ink amount setting step for setting an ink jetting amount of one dot during a flushing operation based upon platen gap adjustment information in such a case that the flushing requirement judging step judges that the flushing operation is required; and a flushing step for flushing ink droplets with respect to a flushing area based upon the ink jetting amount of one dot which is set in the ink amount setting step.
In this case, in the case that the ink jetting amount of one dot during the flushing operation is set in the ink amount setting step, a total number of ink droplets which are jetted from the recording head within a single flushing step is set at the same time.
In addition, in the flushing control method according to the present invention, the flushing requirement judging step is carried out based upon a time counting operation of a flushing timer which is managed while print operation of the recording apparatus is carried out.
In accordance with the recording apparatus of the second embodiment with employment of the above-described flushing control method, while the flushing operation is carried out, the gap adjustment information derived from the platen gap adjustment means is utilized, and also, the ink jetting amount of one dot during the flushing operation is controlled to be adjusted based upon this gap adjustment information. For instance, in such a case that the platen gap is adjusted to be large, the ink jetting amount of one dot is controlled to be increased, as compared with that of such a case that the platen gap is adjusted to be small.
As explained above, in the case that the platen gap is adjusted to be large, since such a control operation is performed so as to increase the ink jetting amount of one dot, even when the jetting distance of the ink droplets is long, the occurrence degree of the ink mist can be suppressed. On the other hand, in this case, since the distance between the nozzle forming surface of the recording head and the impinge positions of the ink droplets is long, such a degree that the ink droplets are rebounded at the impinge positions and then a portion of these rebounded ink droplets is again flied to the nozzle opening can be considerably reduced. Thus, the occurrence of such a print failure, for instance, dot skipping can be suppressed.
Furthermore, in the case that the platen gap is large, such a control operation is carried out. That is, a total number of ink droplets which are jetted from the recording head in a single flushing step may be decreased. As a result, the jetting amount of the ink within a single flushing step may be controlled to a substantially constant range. As a consequence, the recording apparatus can realize the purpose of the flushing operation, and also can suppress the consumption of such ink.